Hydroxyproline oxidase

Hydroxyproline is rapidly metabolized in a pathway initiated by the enzyme hydroxyproline oxidase (Chapter 17). 

The first aspect has been overcome by measurement of urinary hydroxyproline in individuals with an inherited deficiency of hydroxyproline oxidase. Such persons excrete... 

An inborn error of metabolism in which elevated hydrox] proline levels are found in the blood due to a deficiency in ti enzyme, hydroxyproline oxidase. Mental subnormality is feature. 

Figure 3.4 Factors affecting foreign body reaction and potential points of intervention at the level of the myofibroblast (1) inhibit synthesis or release of TGF-P (2) block stimulation by TGF-P of its membrane receptors on the activated fibroblast (3) inhibit the Smad proteins, which transfer the TGF-P effect to the nucleus (4) inhibit transcription of procollagen mRNA (5) inhibit translation of the message to form procollagen (6) inhibit prolyl-4-hydroxylase, which creates hydroxyproline and facilitates helix formation (7) inhibit lysyl oxidase, which cross-links the collagen (8) enhance the function of MMPs, which degrade collagen, or inhibit TIMPs, which degrade MMPs.

Figure 20.19 Biosynthesis and degradation of proline, hydroxyproline and ornithine. Proline oxidase and S-pyrroIine-5-carboxylic acid dehydrogenase are both mitochondrial enzymes. A and B indicate defects in hyperprolinemia I and II, respectively.

Altered collagen formation Impaired lysyl oxidase activity Decreased wound strength because of reduced hydroxyproline content of wound decreased rate of wound healing increased incidence of wound infection... 

Varner, 1988). Extensin is secreted as single soluble monomeric hydroxyproline forms that are slowly insolubilized in the cell wall, probably via the oxidative formation of isodityrosine cross-links (Cooper and Varner, 1983 Fry, 1986a). Wall-catalyzed cross-linking of soluble extensin is inhibited by ascorbate, indicating that this reaction is dependent on an oxidative mechanism (Cooper and Varner, 1984). Thus, it is probable that a cell wall-bound peroxidase-ascorbate oxidase system controls the redox state at the wall, and hence the extensibility of cell wall, by controlling the cross-linking of wall glycoproteins. 

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